Wednesday-Saturday 4/12-4/15

Issued: Wed, Apr 12, 2017 at 8AM

Expires: Sat, Apr 15, 2017

Low avalanche danger in the morning…

Considerable danger in the afternoon with warming!

Warm overnight temperatures will quickly lead to a softening of the sun-affected snowpack and wet (loose/slab) avalanche activity today.

Mind the soft and punchy snow underneath you as it loses its strength and plan your day in tune with solar warmed slopes….limiting exposure the baking snow above you.

As winds are picking up out of the NE, mind newly loaded slopes near ridges and rollovers….especially when new slab sits on sun-crusted southerly aspects.

Friday April 14: VAC Full Moon Spring Fling FUNraiser with Acoustic Avalanche at the Tsaina Lodge.   Grab a date and come boogie! Fire dancing, DJ and raffle too!

Above 2,500ft Considerable

1,800 to 2,500ft Considerable

Below 1,800ft Considerable

Degrees of Avalanche Danger ?

1. Low
2. Moderate
3. Considerable
4. High
5. Extreme

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

WEDNESDAY THURSDAY FRIDAY & SATURDAY

DANGER SCALE

 

WET AVALANCHES:
Elevation:
   Below 5000′
Aspect:
 South, southeast, southwest
Terrain:
Steep terrain near rocks and vegetation.
Sensitivity:
   Touchy when warmed.
Distribution:
   Specific.
Likelihood (Human Triggered):
   Possible
Size:
  Small-Large
Danger Trend:
   Increasing quickly each day with warming temperatures, falling at night
Forecaster Confidence:
   Good

PERSISTENT SLAB:
Elevation:
  Above 2500′
Aspect:
 All
Terrain:
Slopes > 35*
Sensitivity:
   Stubborn on northerlies, Touchy when warmed by sun
Distribution:
   Widespread
Likelihood (Human Triggered):
   Possible
Size:
  Small – Large
Danger Trend:
   Decreasing
Forecaster Confidence:
   Fair

 

AVALANCHE PROBLEM SCALE DESCRIPTORS:

Sensitivity: Non-reactive, Stubborn, Responsive, Touchy
Distribution: Isolated, Specific, Widespread
Likelihood: Unlikely, Possible, Likely, Nearly Certain
Size: Small, Large, Very Large (size scale <here>)
Danger Trend: Increasing, Steady, Decreasing
Forecaster Confidence: Good, Fair, Poor

AVALANCHE PROBLEM TOOLBOX <here>

SNOWPACK DISCUSSION:

Continental (Interior) Specific:  

Winds have increased our of the NE and are moving the recent soft snow to southerly aspects, sometimes resting on sun crust and triggering easily.

Dig and look for buried surface hoar that was found all the way up to ridgeline. Seen still standing under new snow near the summit of Girls Mountain.

The most recent storm produced around 1-2 feet of new snow in the continental region north of 46 mile. The new snow has settled to around 1 foot of medium density powder in areas that haven’t been baked away by the sun. One must travel to elevations around 5000~ feet to find soft powder snow.

There have been reports of the afternoon sun triggering natural avalanches. The first type being wet avalanches which have the potential to slide to the ground. They are most likely to be triggered on southerly aspects especially in elevations below 5000′ when temperatures reach above 32 degrees. The second type being dry slab avalanches consisting of the most recent snowfall. These avalanches are possible on all aspects other than south, realistically anywhere dry powder snow can be found. The warmer temperatures in the afternoon will certainly increase the chances of triggering a slide. 

Generally speaking the base of the snowpack in the interior region consists of sugar snow (basal facets). This is poor support for the rest of the snowpack and leads to the possibility of the entire season’s snowpack ripping out in a massive avalanche. These slides are most likely to be triggered in the afternoon sun.

Sharing your observations creates an informed community.

Recent Avalanche Activity

Continental (Interior) Specific: 

  • March 31: skier triggered size D2 avalanche at 3500′ North aspect. 40-60cm storm slab failed on buried near surface facets with a old windslab as the bed surface. A possible sympathetic released lower on the same slope, with a crown depth 60-100cm, harder slab.

Recent Weather

See Maritime Zone for updated weather.

Additional Info & Media

Weather Quicklinks:

SNOW CLIMATE ZONES:

  • coastal-zone-iconMaritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • intermountain-zone-iconInter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • interior-zone-iconContinental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).

Photo of Thompson Pass

thompson-pass-ski-runs

Interactive Map of Valdez Forecast Areas w/ Many Resource Layers (Trevor Grams)

climate-zones-topoclimate-zones-satellitegoogle-earth1

Run Map of Thompson Pass Area (Sean Wisner) (2MB download)
VAC Run Map Thompson Pass

NEWS: Our region is “one of the snowiest places on earth” – Serendipity / Rendezvous snowfall record set in 1963 <here>.

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Posted in Continental Forecasts.

Forecaster: Kevin Salys